Elected to the Manitoba Legislature at the general election in December 1899, defeating Conservative challenger John A. Davidson, he resigned his seat in February 1900 citing pressure on him by the Conservative government of Hugh John Macdonald. Davidson subsequently won the seat at a by-election. Ennis lived at Neepawa for a time then moved to Seniac, Saskatchewan around 1909. He died at Brandon on 13 November 1925, survived by a widow and three sons.